Many portable products, such as cell phones, laptop computers, personal digital assistants (PDAs) or the like, incorporate one or more processors executing programs that support communication and multimedia applications. A processor for such products conventionally has a hierarchical memory configuration with multi-levels of caches including an instruction cache, a data cache, and system memory. The processor may need to operate with high performance and efficiency to support the plurality of computationally intensive functions for such products.
Further, the processor may be pipelined and support execution of conditional branch instructions. The execution of a conditional branch instruction in a pipelined processor may stall the pipeline pending the determination of the condition. To avoid stalling the processor, some form of branch prediction may be employed early in the pipeline. The branch prediction may allow the processor to speculatively fetch and execute instructions based on a predicted branch behavior.